1. Field of the Invention
The present invention relates to a wireless networking device and a communication method using the same, and, more particularly, to a wireless networking device and a communication method using the same that performs a hand off between wireless networks without difficulty.
2. Description of the Related Art
As mobile communication devices become widely used, the demand for Internet services in wireless environments increases. Also, users want to use the Internet with mobility.
Thus, studies are being actively conducted on wireless LANs, mobile IPs, and Mobile Ad Hoc Networks (MANETs) to provide users with wireless Internet services.
MANET refers to a solution which is linked to IPv6 (Internet Protocol version 6) and which gives internet access to a home network which connects all terminals in a home wirelessly or in a wired manner, and to mobile devices to support wired and wireless data communication.
Ipv6 is an upgraded version of Ipv4 and is compatible with Ipv4. Also, Ipv6 is designed to efficiently operate in low speed networks, as well as in high speed networks such as ATM networks.
As more devices accessed the Internet using Ipv4, the number of addresses allotted to devices became insufficient. Thus, the priority in developing Ipv6 is to increase the number of devices that can access the Internet. The address size of Ipv6 is 128 bit, which is an increase from the 32 bit addresses of Ipv4.
FIG. 1 illustrates a configuration of a conventional wireless network. A gateway 11 of a predetermined wireless network 10 transmits router information to a plurality of mobile devices existing in a corresponding wireless network to automatically set an address and to perform other tasks.
The router information comprises an address and a lifetime of the gateway 11. The respective mobile devices check which mobile network they reside in and automatically set the address.
Meanwhile, as a plurality of mobile devices access the external network through the gateway 11, a bottleneck occurs between the gateway 11 and the mobile devices adjacent to the gateway 11.
Accordingly, two gateways 11 and 12 may be installed in the mobile network 10, as shown in FIG. 2, to reduce the bottleneck and delay time of the packet transmission.
If a plurality of gateways 11 and 12 are used as shown in FIG. 2, a care of address is generated by a function that automatically generates IPv6 addresses, and the gateways 11 and 12 transmit a neighbor solicitation (NS) message to mobile devices adjacent to them to confirm whether other mobile devices in the MANET use the generated care of address. Specifically, the gateways 11 and 12 determine that the care of address is not repeated if there is no response for a predetermined period of time after transmitting the NS message to adjacent mobile devices.
Also, the respective mobile devices receive the router information from the plurality of gateways to access the external network through closer gateways. Accordingly, if the closer gateways are different from the previous gateways, a hand off should be performed.
The MANET comprises at least one gateway mobile device that is adjacent to or multiple hops away from the gateway. The MANET may not detect whether the address of the mobile device that is two or more hops away is repeated through the technique which detects repeated addresses of mobile devices only one hop away from the device itself.
Thus, a method is required to avoid packet transmission delay due to a shortage of the gateways and to detect, more reliably, a repeated address in a MANET having multiple hops.
Korean Patent Unexamined Publication No. 2004-0045188, incorporated herein by reference, discloses a method of managing a routing table using an IPv6 interface ID, which manages a routing table by using an inherent interface ID for respective interfaces, and prevents multiple source address confusion in a routing table. However, the method is provided to settle routing confusion that may occur by designating multiple IPv6 link local addresses to a single interface, but it is inappropriate for detecting a repeated address between mobile devices that are multiple hops away from a gateway while the mobile devices perform the hand-off.